1. Field of the Invention
This invention relates to milling cutters and, more specifically, to a milling cutter having indexable inserts secured with a wedge-type clamp capable of high speed operation.
2. Description of the Prior Art
A major factor affecting the design of milling cutters utilizing indexable inserts about the periphery of the milling cutter body is the influence of centrifugal forces upon the indexable inserts and upon the hardware utilized to retain the indexable inserts within the milling cutter body. These centrifugal forces increase by the square of the rotational speed with a linear increase in rotational speed.
U.S. Pat. No. 3,733,665 discloses a rotary cutting tool utilizing a wedge clamp urging the insert against a pocket in the cutting tool. However, as the rotational speed of the cutter increases, the wedges which are restrained by pitch screws may move radially outward thereby lessening the compressive force upon the insert. At higher speeds the wedge may become disengaged from the insert thereby permitting the insert to fall from the cutter body.
U.S. Pat. No. 5,716,167 entitled "High Speed Cartridge Type Milling Cutter," assigned to Kennametal Inc. and hereby incorporated by reference, discloses a milling cutter utilizing a cartridge mounting mechanism having a dovetail configuration which is positively restrained within a matching dovetail configuration in the cutter body. Indexable inserts are connected to the cartridge utilizing tangentially mounted screws. While the insert cartridge may be restrained against outward radial movement during high rotational speeds, the mounting screw of the indexable inserts will be subjected to shear, and this will be a limiting factor in the rotational speed.
An object of the subject invention is to provide a milling cutter with indexable inserts clamped therein which is capable of securing the inserts within the milling cutter body such that the milling cutter body is tolerant of high speeds and such that the clamping force upon the insert by the milling cutter body increases as the rotational speed of the milling cutter increases.